The present invention relates to an earphone. Specifically, this invention relates to an earphone having a bushing that holds a cord running from a main body of the earphone.
A known earphone is equipped with a main body, a speaker unit installed in the main body, a cord connected to the speaker unit at one end thereof and running from the main body, and a bushing that holds the cord that is running from the main body. Such a known earphone is disclosed, for example, in Japanese Un-Examined Patent Publication No. 2001-333484.
In a known earphone, a main body consists of a plurality of housings.
Specifically, in one type of known earphone, a main body contains a speaker unit and consists of a front housing and a rear housing. The front and rear housings are combined to constitute the main body so that the front one is located at the side of a user's head whereas the rear one is located at the outer side when the earphone is attached to the auricle of the user's ear. The front and rear housings are combined to each other by ultrasonic welding or an adhesive.
Provided at the rear side of the speaker unit in the main body is a back cavity that is a space surrounded by the inner surfaces of the front and rear housings.
The space of the back cavity and the outer space are partitioned only by the front or rear housing. The front and rear housings are usually made by resin molding and hence not so excellent in sound isolation. Thus, the sound emitted at the rear side of the speaker unit travels through the front or rear housing without isolated enough and leaks to the outside of the main body.
Moreover, when the front and rear housings are combined by ultrasonic welding, the faying portions of the housings are joined to each other by point welding with gaps being created between the faying surfaces thereof.
Such gaps are also created between the faying surfaces of the front and rear housings when the housings are combined by an adhesive. This is because it is difficult to apply the adhesive on the faying surfaces so as not to create the gaps in mass production.
Accordingly, it is difficult to avoid the gaps between the front and rear housings when the housings are combined by ultrasonic welding or an adhesive. The sound that leaks from the gaps is comparatively larger than that leaking from the other parts of the main body.
There is a demand for earphones with smaller sound leakage that can be used in a specific environment (such as, in a train) where it is preferable not to leak sounds.